1. Technical Field
This application generally relates to data storage, and more particularly to techniques used in connection with device identifiers.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units, logical devices, or logical volumes (LVs). The logical disk units (e.g., such as may be presented to the host as LUNs or logical unit numbers) may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
Each of the data storage devices or volumes of the data storage system as exposed or presented to the host may be bound to a device identifier, such as a WWN (world wide name). The host may use the identifier in connection with directing I/O operations to the device such as I/O operations from an application having its data stored on a storage device bound to the identifier. Existing systems provide a static binding of identifier to the data storage device where the data storage system controls such static bindings and informs the host regarding such defined static bindings, for example, in response to the host performing discovery processing to discover paths from the host to data storage system devices. There are problems with the foregoing static bindings such as in connection with various use cases. For example, data used by the application may be migrated from a first storage device having a first device identifier to a second device having a second device identifier. In this manner, changes are required in connection with the host and/or application to use the second device identifier rather than the first device identifier. Such changes to use the new second device identifier may be disruptive to the application and may include, for example, reconfiguring and/or rebooting the host and/or application.